EVALUATION OF A TECHNIQUE FOR SAMPLING BLOOD FROM SMALL FISHES

A technique has been developed for extracting small quantities of bloo d, up to 16 mu l, from fish of 20-30 mm total length, from the dorsal aorta of decapitated fish. This method can provide up to 4 mu l of blo od from fish of total length 10 mm. This method compares favourably wi th the well established technique of caudal peduncle severance in larg er fish; no significant difference was found between the two technique s for plasma osmolality, HGBC, WBCC and HCT.